Method and apparatus for using hydroxyl to reduce pollutants in the exhaust gases from the combustion of a fuel

Abstract

A method and apparatus are provided for reducing pollutants in the exhaust gases produced from the combustion of a fuel by introducing hydroxyl and associated radicals and oxidizers into at least one of the precombustion and postcombustion gas stream of the combustion engine upstream of the catalytic converter and treating the exhaust gases with the catalytic converter.

What is claimed:  
     
       1. An apparatus for improving the performance of a catalytic converter to decrease from a first concentration to a second lower concentration at least one pollutant selected from the group consisting of products of incomplete combustion and oxides of nitrogen produced by the combustion of fuel in an internal combustion engine, comprising: 
       a combustion chamber;  
       a passageway for channeling at least a portion of a post-combustion gas stream;  
       at least one hydroxyl radical generator adapted and configured to introduce hydroxyl radicals into the post-combustion gas stream;  
       a power supply adapted and configured to provide high frequency current to the at least one hydroxyl radical generator; and  
       at least one catalytic converter, which contains catalytically active material, located in the post-combustion gas stream, wherein at least a portion of the catalytically active material Is located downstream from the at least one hydroxyl radical generator,  
       wherein exhaust gases are formed from the combustion of a fuel in the combustion chamber and at least, a portion of the exhaust gases is exposed to the at lest one hydroxyl radical generator before being exposed to at least a portion of the catalytically active material in the catalytic converter.  
     
     
       2. The apparatus according to  claim 1 , wherein the generator contains at least one ultraviolet lamp having a wavelength between about 100 nanometers and about 200 nanometers. 
     
     
       3. The apparatus according to  claim 1 , wherein the generator contains at least one electric discharge device. 
     
     
       4. The apparatus according to  claim 3 , wherein the at least one electric discharge device, comprises: 
       at least one first electrode;  
       at least one second electrode; and  
       at least one dielectric barrier positioned between the first electrode and the second electrode.  
     
     
       5. The apparatus according to  claim 1 , wherein the power supply provides high frequency current having a frequency of at least about 1,000 Hz. 
     
     
       6. The apparatus according to  claim 1 , wherein the generator is adapted and configured to be powered substantially whenever exhaust gases are produced. 
     
     
       7. The apparatus according to  claim 1 , wherein the internal combustion engine is a diesel engine. 
     
     
       8. The apparatus according to  claim 1 , wherein the internal combustion engine is a spark-ignition engine. 
     
     
       9. The apparatus according to  claim 1 , wherein the power supply supplies low power. 
     
     
       10. The apparatus according to  claim 1 , operated in the absence of any reducing agent added to the post-combustion gas stream. 
     
     
       11. The apparatus according to  claim 1 , wherein the generator is separated from the catalytic converter by a predetermined distance. 
     
     
       12. The apparatus according to  claim 1 , wherein the power supply is adapted and configured such that the voltage and current may be varied by a controller that monitors engine operating conditions. 
     
     
       13. A method for improving the performance of a catalytic converter to decrease from a first concentration to a second lower concentration at least one exhaust gas pollutant selected from the group consisting of products of incomplete combustion and oxides of nitrogen produced by the combustion of a fuel in an internal combustion engine, comprising: 
       combusting a fuel and forming exhaust gases in a combustion chamber;  
       channeling the exhaust gases into a post-combustion gas stream;  
       exposing at least a portion of the exhaust gases to at least one hydroxyl radical generator located in the post-combustion gas stream;  
       providing high frequency power to the at least one hydroxyl radical generator; and  
       passing at least a portion of the exhaust gases that were exposed to the at least one hydroxyl radical generator through at least one catalytic converter, which contains catalytically active material, located in the post-combustion gas stream, wherein at least a portion of the catalytically active material is located downstream from the at least one hydroxyl radical generator.  
     
     
       14. The method according to  claim 13 , wherein the generator contains at least one electric discharge device. 
     
     
       15. The method according to  claim 14 , wherein the at least one electric discharge device, comprises: 
       at least one first electrode;  
       at least one second electrode; and  
       at least one dielectric barrier positioned between the first electrode and the second electrode.  
     
     
       16. The method according to  claim 13 , wherein the power supply provides high frequency current having a frequency of at least about 1,000 Hz. 
     
     
       17. The method according to  claim 13 , wherein the generator is adapted and configured to be powered substantially whenever exhaust gases are produced. 
     
     
       18. The method according to  claim 13 , wherein the power supply supplies low power. 
     
     
       19. The method according to  claim 18 , wherein the power supply is adapted and configured such that the voltage and current may be varied by a controller that monitors engine operating conditions. 
     
     
       20. The method according to  claim 13 , performed in the absence of any reducing agent added to the post-combustion gas stream. 
     
     
       21. An apparatus for decreasing from a first concentration to a second lower concentration at least one exhaust gas pollutant selected from the group consisting of products of incomplete combustion and oxides of nitrogen produced by the combustion of fuel in a diesel engine, comprising: 
       a passageway for channeling at least a portion of a post-combustion gas stream from the engine;  
       at least one hydroxyl radical generator adapted and configured to introduce hydroxyl radicals into the post-combustion gas stream in the passageway;  
       a power supply adapted and configured to provide current having a frequency of at least about 1,00 Hz to the at least one hydroxyl radical generator; and  
       at least one catalytic converter, which contains catalytically active material, located in the passageway, wherein at least a portion of the catalytically active material is located downstream from at least one hydroxyl radical generator,  
       wherein at least a portion of the exhaust gases formed from the combustion of fuel in the internal combustion engine is exposed to at least a portion of the at least one hydroxyl radical generator before being exposed to at least a portion of the catalytic converter, wherein the apparatus is adapted and configured to produce hydroxyl radicals substantially whenever the internal combustion engine is producing exhaust gases end the apparatus is adapted and nonfigures such that no additional reducing agent is added to the exhaust gases produced from the combustion of the fuel.  
     
     
       22. The apparatus according to  claim 21 , wherein the at least one hydroxyl radical generator is an electric discharge device, comprising: 
       at least one first electrode;  
       at least one second electrode; and at least one dielectric barrier positioned between the at least one first electrode and the at least one second electrode.  
     
     
       23. The apparatus according to  claim 21 , wherein the generator is separated from the catalytic converter by a predetermined distance.